最近在做APP的時候，有時候當打開WebView(WKWebView)的時候, App 只會在我的設備上崩潰環境為 Mac OS 10.12.1 + Xcode 8.2 + iOS 10.2.1, 刪掉App、 重啟手機、 重啟Xcode、 移除DerivedData都不能解決這個問題， 最后重啟電腦才解決。
堆棧錯誤如下：
* thread #1: tid = 0x11a50, 0x00000001937306f0 JavaScriptCore`JSC::JSGlobalObject::~JSGlobalObject() + 36, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x10a2abe28)
frame #0: 0x00000001937306f0 JavaScriptCore`JSC::JSGlobalObject::~JSGlobalObject() + 36
frame #1: 0x00000001937306b4 JavaScriptCore`JSC::Heap::FinalizerOwner::finalize(JSC::Handle<JSC::Unknown>, void*) + 24
frame #2: 0x0000000193f15fe0 JavaScriptCore`JSC::WeakBlock::lastChanceToFinalize() + 80
frame #3: 0x0000000193daaeb4 JavaScriptCore`JSC::MarkedBlock::lastChanceToFinalize() + 40
frame #4: 0x0000000193daa2e8 JavaScriptCore`JSC::MarkedAllocator::lastChanceToFinalize() + 96
* frame #5: 0x0000000193dab670 JavaScriptCore`void JSC::MarkedSpace::forEachAllocator<JSC::LastChanceToFinalize>() + 92
frame #6: 0x0000000193bdb7dc JavaScriptCore`JSC::Heap::lastChanceToFinalize() + 128
frame #7: 0x0000000193ebf310 JavaScriptCore`JSC::VM::~VM() + 220
frame #8: 0x00000001936852d4 JavaScriptCore`JSC::JSLockHolder::~JSLockHolder() + 84
frame #9: 0x0000000193caf648 JavaScriptCore`JSContextGroupRelease + 80
frame #10: 0x0000000193d5a8d4 JavaScriptCore`-[JSVirtualMachine dealloc] + 36
frame #11: 0x0000000193cae958 JavaScriptCore`-[JSContext dealloc] + 140
frame #12: 0x0000000193f40d58 JavaScriptCore`WTF::RunLoop::TimerBase::timerFired(__CFRunLoopTimer*, void*) + 44
frame #13: 0x000000018f7271d8 CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 28
frame #14: 0x000000018f726eec CoreFoundation`__CFRunLoopDoTimer + 872
frame #15: 0x000000018f7267a8 CoreFoundation`__CFRunLoopDoTimers + 244
frame #16: 0x000000018f7243a4 CoreFoundation`__CFRunLoopRun + 1572
frame #17: 0x000000018f6522b8 CoreFoundation`CFRunLoopRunSpecific + 444
frame #18: 0x0000000191106198 GraphicsServices`GSEventRunModal + 180
frame #19: 0x00000001956997fc UIKit`-[UIApplication _run] + 684
frame #20: 0x0000000195694534 UIKit`UIApplicationMain + 208
frame #21: 0x00000001001da8b4 TravelApp`main(argc=1, argv=0x000000016fd83940) + 124 at main.m:14
frame #22: 0x000000018e6355b8 libdyld.dylib`start + 4
最后再一次偶然的情況下，才發現問題的根源是 Safari Web Insepector
原因是我使用這個工具Debug App中的網頁內容， 打開Safari 中的Develop Tool, 并且僅當Automatically Show Web Inspector for JSContexts 被勾選的情況下才會出現。
Paste_Image.png
嚴重懷疑這個是iOS 10.2.1的Bug， 因為在之前并沒有出現過??。
